Each winter for the past several years, I have kept watch for the season's first Bohemian waxwings. It's not that I do anything special; I simply listen and look for signs of their presence, just as I do for the black-capped chickadees, red-breasted nuthatches, ravens and other birds that inhabit the Anchorage area.

For almost a quarter century, birds have been among my favorite neighbors, inevitably brightening my day, and I like to take note of them. I've even gotten in the habit of compiling an informal list of the species I observe each day, and recording them in my Anchorage nature journal. In late spring and early summer, the list is long, with dozens of bird species. In late fall and then through winter, the list is much shorter, sometimes only a handful.

This year I spotted a flock of 10 waxwings on Oct. 19 while walking at Kincaid Park. Those were early arrivals, and more than a month would pass before I noticed any others. Looking at my notes from that date, I see the afternoon was partly sunny with a brisk wind (at least in West Anchorage) and a high of 41 degrees at my house. Other birds I saw or heard that day included black-capped and boreal chickadees, nuthatches, magpies, three spruce grouse, a raven and gull.

It's always a pleasure to add waxwings to my bird list. For starters, they fly clear of the city for most of the year, only descending upon Anchorage in late fall or early winter, when wild foods become scarcer, to feast upon an abundance of locally grown fruit. They inhabit our community in substantial numbers for only a few months every year, during a time — the depths of winter — when avian diversity has bottomed out.

Though their general patterns are known, much about the waxwings remains a mystery. It's uncertain where all these widely roaming "gypsy birds" (thus the Bohemian tag) spend their time before settling into Anchorage; what specifically triggers their migration to the city; why their numbers vary widely year to year; where they go after they depart; and how long they remain in large flocks before dispersing.

More to like about Bohemians: among the most handsome of northern birds, waxwings add beauty to the winter landscape (and sky). Their plumage is a mostly gray "suit" of silky feathers, tinted russet around their crested heads. Their feathered bodies are further decorated by a tail edged in yellow, a black eye mask and white-striped wings that bear the small red "wax" bars that give the birds their name.

Waxwings' voices are as pleasing as their physical appearance, a gentle, reedy trilling that to my sensibilities has a calming effect.

Their behavior, too, is delightful to observe. They typically enter Anchorage singly, in pairs or small groups, drawing little attention. As the days and weeks pass, they coalesce into ever-larger flocks, until by December multitudes of them swirl through local skies. The largest groups may include thousands of birds. Longtime Anchorage birder Dave DeLap once told me that he'd seen flocks of 3,000 or more waxwings and knew others who'd watched 5,000 swooping through local skies.

In flocks big and small, they circle and dive in synchronized flight while roaming from neighborhood to neighborhood and street to street, descending on yards and greenbelts to strip ornamental trees of their fruits, feasting on mountain ash berries, elderberries, chokecherries and crab apples.

For all their beauty and occasional abundance in Anchorage, I didn't really notice waxwings until the mid-1990s, after I began discovering the many birds that inhabit our local landscape. Like the black-capped chickadees that opened up my world in 1993 (only a couple of weeks before I celebrated my 44th birthday), waxwings have become symbols of the way my world can expand and become richer if I take the time to pay attention to — and appreciate — what's going on around me, big or small.

Huge flocks

After settling on the Hillside in 1993, I rarely saw waxwings in my neighborhood until 2004, when scores of them passed through. Perched on spruce and birch trees, they trilled on and on. I wrote in my home journal: What are they doing here? What's luring them in? Have my neighbors been planting ornamentals?

Inspired by their visit, I decided to track down one of Anchorage's larger flocks and spent some unhurried moments enjoying the birds' frenzied company. I didn't know it at the time, but unprecedented numbers of Bohemians had invaded the city that year — a record 11,415 Bohemians were sighted during Anchorage's 2004 Christmas Bird Count. (That record would be shattered five years later, when 22,245 Bohemian waxwings were counted.)

At midday in late December of that year, I grabbed binoculars and a journal, jumped in my Toyota and headed downhill toward the northwest part of town. It was a fine day to chase waxwings: clear and cold, with only a light breeze. In a neighborhood near Westchester Lagoon I watched hundreds of waxwings swarm fruit trees and then lift off and fill the sky above me, sometimes in unified formation, other times in more chaotic swirling.

They went round and round in ever-widening circles, as if uncertain where to go, or perhaps engaged in some avian form of follow the leader. After several go-rounds, they began to spin off in smaller groups until finally they all disappeared.

That should have been enough. But hungry for more, I left the lagoon area and drove to Northern Lights Boulevard, heading west. With no real goal in mind, I turned right onto Turnagain Parkway. Moments later, nearing an intersection, I pulled over and turned off the engine. I knew my quest had ended. I'd entered waxwing heaven.

At every corner, trees were filled with beautiful birds. Some gobbled mountain ash berries; others nibbled crab apples and still more pecked at the seedpods of a third kind of ornamental tree. As at Westchester Lagoon, waxwings constantly flew in and out, alternately eating and perching. Opening my window, I savored the soft murmur of hundreds of contented birds. Every now and then, they would fly off, circle around, then return.

Shortly after 3 p.m., about a half hour until sunset, the birds again lifted off. This takeoff, I sensed, was different than the earlier ones. Hundreds of birds circled above the neighborhood, their rapidly beating wings flickering in the golden late-afternoon sunshine like holiday lights. Then, as if by some signal, hundreds more waxwings approached from the west. Others flew in from the east.

The entire sky above me was filled with trilling, flickering birds. How many, I can't say, but easily more than a thousand. Maybe double or triple that. Then, as if by magic, they were gone.

Two years later, I moved off the Hillside to a street in West Anchorage not far from where I'd witnessed the spectacle. And for the past decade, my mid-winter days have been regularly blessed by waxwings. And every now and then, they've stopped me with unexpected behaviors.

A Bohemian waxwing tosses up a mountain ash berry before catching it while feeding on Government Hill near downtown Anchorage on Thursday, Jan. 5, 2017. (Bill Roth / Alaska Dispatch News)

One year I watched wave after wave of softly trilling waxwings sweep out of the birch-cottonwood forest that borders a section of the Coastal Trail near my home and fly, with rapid wing beats, over the snow-and-ice-covered mudflats that border Anchorage's western fringes. Never had I seen them flying in such numbers, or so far, out onto the mudflats. The birds shrank into tiny dots and I guessed them to be a half mile away, maybe more.

The waxwings dispersed as they looped over the flats. Some landed. Others circled back and returned to the forest. As they approached where I stood, another bunch headed for the inlet. There was a constant back and forth between woods and flats, as if the waxwings were taking turns or flying in shifts.

The longer I watched, the more birds I saw. Hundreds in all. Now and then, scores of them formed a small, dark cloud as they lifted off the flats, then settled back down on a different patch of snow and ice. They seemed bunched up near the water and I wondered if the salt deposited by recent tides attracted them. I've occasionally seen other birds picking at snow-covered driveways and roadways and guessed them to be eating salt. What else could explain this odd behavior?

None of the local birders I contacted afterward had seen waxwings flocking to the flats in such large numbers and more than one agreed it seemed "very strange." Stan Senner, then executive director of Audubon Alaska, suggested that the Bohemians were likely picking up grit rather than salt, to help break down the skins of berries they consumed.

This makes sense to me. Yet in the nine winters since, I haven't seen the behavior repeated.

No fear

More recently, while walking through my neighborhood on an early winter day, I watched a flock of waxwings take on a goshawk.

Only a few of the birds initially caught my attention, wings beating rapidly in their telltale way. That handful soon grew into a dozen, then two dozen and more.

The waxwings circled in tight formation, some breaking ranks to form their own spinning groups. Chill forgotten, my full attention now on the birds, I watched them converge on a tall cottonwood tree, limbs bare in the early winter grayness.

In the birch's upper limbs was a much larger bird, a raptor, huddled as if in response to the cold, stinging wind. But in fact that bird — whose size, shape and coloring suggested a northern goshawk — was hunkered down against the ranks of songbirds that had come to harass it.

It is always an amazing thing to watch the way that groups of songbirds fearlessly "mob" a much larger bird of prey, one that given the opportunity (often through the element of surprise) would attack, kill and eat the much smaller creatures pestering it.

Scientists tell us that such mobbing behavior is a cooperative anti-predator strategy, most commonly used by birds during their breeding season. Yet much remains to be learned about mobbing and why — or when — it occurs. In winter these waxwings had no young to protect, but clearly the goshawk's presence riled them up.

What I witnessed might simply have been an instinctive group response to a natural enemy, in a circumstance when waxwings emboldened by the strength of numbers found a goshawk who couldn't benefit from its usual hunting strategy, the stealth attack. Still, that waxwings would choose to take on a raptor famous for its ferocity strikes me as impressive. And I find it curious that the goshawk made no attempt to attack the much smaller and less powerful songbirds, even when a few of them perched on branches a few feet away.

The number of waxwings circling the birch tree grew until several dozen were joined in synchronized flight. Where did they all come from, and so quickly? Had their trilling voices somehow changed in tenor and volume, to alert others of their kind who happened to be in the area? The goshawk refused to budge, patiently enduring the magnified insults of the much smaller birds.

I'm not sure how long I watched. Ten minutes? Fifteen? Longer? However long it was, before long the bulk of the waxwing mob began flying off to the west and it appeared that the confrontation was approaching an end. Still, a few of the waxwings continued to stake out the goshawk, some circling and others perched.

Perhaps figuring it wise to depart while its tormentors were few — and with no assurance that the larger flock wouldn't return — the raptor suddenly dived from the branch and dipped low. Then, with strong beats of its large wings (strong enough to strike down a waxwing, should one get too close), the goshawk flew east, past house after house of people who had no idea of the drama unfolding outside their homes.

Because my sympathies were with the songbirds, I couldn't help but smile when the waxwings, still hovering around the cottonwood tree, gave chase. And then, apparently circling back, the larger flock joined in the pursuit.

Hundreds of birds

One other memorable encounter happened only a few minutes' walk from my home.

Upon returning from shopping, I discovered my neighborhood swarming with waxwings. Hundreds of them were perched on the birches and spruces that line nearby streets. Hundreds more whirred among the treetops, zoomed down the streets at head level and looped through residential yards. Still others gulped small red fruits that hung from my neighbors' crab apple trees.

If the Bohemians' behavior on the coastal flats and in taking on the goshawk had inspired wonderment and a sense of mystery, this gathering lifted me into pure delight. It is an absolute treat to stand among hundreds, perhaps thousands, of birds as they swirl through one's neighborhood.

Face lit by a smile, I headed for an apple tree blurred by hundreds of beating wings. It was 4:40 p.m., 12 minutes past sunset, but the dimming light seemed to deepen, rather than dampen, the waxwings' appetites.

The birds largely ignored me as I approached within 10 feet of their feeding tree. Dozens shuffled upon the snow, grazing on small red fruits that had fallen from branches or been dropped by other waxwings. Others hung from tree limbs, plucking the apples — no bigger than store-bought cherries — and gobbling them down.

There was a constant coming and going of waxwings. They flew in and out of the yard like accelerated tides, back and forth, back and forth. Now and then, nearly all of the apple eaters would leave at once, for unclear reasons, their departure accompanied by a loud whoosh.

Waxwings streaked past, occasionally close enough that I could feel the tickle of their wing beats.

Shortly before 5 p.m., as if by some signal among themselves, the waxwings began leaving in large numbers. A few dozen detoured to another crab apple tree and ate from its branches or scavenged fruit from the snow-covered yard and stretch of road it overhangs. But they didn't stay long this time.

Many of the waxwings circled around the neighborhood before departing. But from what I could tell, most, if not all, eventually flew to the west. Where they stay at night is uncertain, one of the Bohemians' many mysteries, but I imagined they would settle into some of West Anchorage's more densely wooded areas.

Only a few softly trilling birds remained as I walked up the steps to my house, the neighborhood settling into a still darkness.

Trilling song

None of my encounters with waxwings this winter have been as amazing or bewildering as those past experiences. But every time I see or hear them, they lift my spirit. Although I have no fruit trees in my yard, waxwings occasionally perch in the spruce, birch and cottonwood trees that grow nearby, and they inevitably sing in their softly trilling way. Whatever I'm doing, I pause and savor their voices.

And more often than not, I'll whisper thanks to the waxwings, who seasonally grace my neighborhood, and our city, with the beauty of their forms, songs and flight — bringing good cheer with their exuberant feasting and great swirling presence.

Anchorage nature writer Bill Sherwonit is the author of more than a dozen books, including "Animal Stories: Encounters with Alaska's Wildlife."